Organophosphorus pesticide quinalphos (Ekalux 25 E.C.) reduces sperm functional competence and decreases the fertilisation potential in Swiss albino mice.

Abstract

Quinalphos (QP)is one of the most commonly used organophosphate pesticide for agriculture. In this study,adultSwiss albino male mice were orally administered with 0.25, 0.5 and 1.0mg/kg of QP (Ekalux 25 E.C.) for ten consecutive days and the reproductive function was assessed at 35 and 70days after QP treatment. At highest dose (1.0mg/kg), QP exposure resulted in significant decrease in motility and increase in sperm head defects and DNA damage. Pharmacokinetic data showed a threefold increase in concentration of QP in the testis as compared to serum. QP was detectable in testes even after 24hr of administration indicating slow clearance from tissue. In addition, high oestradiol,low testosterone levelwith a parallel increase in aromatase and cytochrome P450 transcript levelswas observed. Significant decrease in fertilisation, lowerblastocyst rateand poor blastocyst quality was observed when spermatozoa collected from QP exposed mice were subjected to in vitro fertilisation. In conclusion, exposure of QP to male mice decreases the sperm functional competence and fertilising ability, whichappears to bemediated through elevated oxidative stress and altered steroidogenesis in testes.